DTC P0111: Intake Air Temperature Sensor Gradient Too High: Description

Fig 1: Resistance And Temperature Graph

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• The intake air temperature sensor, mounted in the mass air flow meter sub-assembly, monitors the intake air temperature. The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature becomes low, the resistance of the thermistor increases. When the temperature becomes high, the resistance drops. These variations in resistance are transmitted to the hybrid vehicle control ECU as voltage changes (See Fig. 1).
• The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the hybrid vehicle control ECU, via resistor R which is located inside the hybrid vehicle control ECU.
• Resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes, according to changes in the intake air temperature, the voltage at terminal THA also varies. Based on this signal, the hybrid vehicle control ECU increases the fuel injection volume when the engine is cold to improve driveability.

DTC No.	DTC Detection Condition	Trouble Area
P0111	When either of following conditions are met (2 trip detection logic): In the time period between the warm engine being stopped and the next engine start, change in intake air temperature sensor output below threshold During engine warm up after a cold engine starts, change in intake air temperature sensor output below threshold	Mass air flow meter sub-assembly